Field
The present disclosure relates generally to network switches typically used in data centers, and more particularly to network switches providing additional port capabilities that become active in the event of a failure occurring in a primary port, or that may be used for additional purposes.
Description of the Related Art
Current data network switch architectures have a finite number of ports 108 in the switching core, as seen in FIG. 1. This therefore means that a switch of a given size uses all its available ports for switching data between the ports (primary ports 108), leaving no active ports available to compensate in case of a primary port 108 failure. A network switch consists of a number of interface ports 108, switch logic 106, and a control processor 102. Some network switches may also have dedicated packet processors to perform routing and other functions. A network switch may also have a Management Interface Port 104 that enables the switch to communicate with Management Controller 100 that configures the settings within the Network Switch 10.
Each port 108 connects to Switch Logic 106 via data path 112. In operation, Switch Logic 106 receives data from a particular port 108 and transfers or switches the data to an outgoing port 108 as defined by configuration settings from the Management Controller 100. FIG. 2 shows more details of a connection between two ports 108 within the Switch Logic 106. The basic function of a Network Switch 10 consists of receiving a physical layer data stream on an input port 108, extracting the data, and then transmitting that data out as a physical layer data stream on an output port. The two main blocks for this process within the Network Switch are transceiver ports 108 to external medium 118 and Switch Logic 106 which in turn contains a number of functional blocks.
A port 108 consists of a transceiver 132 and a connector 130. The transceiver 132 has a receiver which receives the data from a remote end via external medium 118, and a transmitter which transmits the data to a remote end via an external medium 118. Examples of external mediums include wireless, Cat 6, Cat 6a, optical fiber, or other physical connection mediums. In a network switch, a port 108 receives a physical layer data signal from the external medium 118, which then converts the signal from the physical layer signal into an electrical data signal, separates the recovered timing information from physical layer signal, and clocks the data via connection 112 into a Serial/Deserializer 120 (SerDes) as a serial data stream. The SerDes 120 converts the serial data stream from the receiver into a parallel interface format for the next stage, a Media Access Control (MAC) layer 122. The MAC layer 122 is an interface between the Logical Link Control (LLC) sublayer and the network's physical layer and provides the Data Link Layer functions including the frame delimiting and identification, error checking, MAC addressing, and other functions. The frame delimiting and identification functions are the functions that locates packet boundaries and extracts the packets from the incoming data stream. The packet is parsed by the MAC layer 122 and the header fields are extracted and passed via interface bus 110 to the Central Processing Unit (CPU) 102, or a dedicated Packet Processor (not shown), which interprets the header information. In an Ethernet packet for example, the header contains the source MAC address, destination MAC address, and other information needed to determine the packet type and destination of the packet. The Network Switch 10 is configured by the Management Controller 100 which communicates with the Management Interface Port 104 via control path 101 to exchange information, such as configuration information, alarm information, status information. The Routing Tables 128 contain the information necessary to direct an incoming packet on a particular port 108 to an outgoing packet on a particular port 108. The Routing Tables 128 may be determined by discovery protocol software within the Network Switch 10, or the CPU 102 may receive configuration information from the Management Controller 100 to set up particular routing table configurations. CPU 102, or the dedicated packet processor, looks up the output destination route for the packet, modifies the outgoing header if necessary, then the Switch Fabric 124 transfers the packet to an outgoing queue in the MAC 122. The outgoing MAC layer 122 formats the outgoing packet for transmission and performs such functions as generating the frame check sequence for the outgoing packet. The completed packet is then fed to the outgoing SerDes 120, which converts the parallel data stream into a serial data stream. The serial data stream is fed to the outgoing transceiver port 108 which converts the data stream into a physical layer signal, adds in the physical layer timing and transmits the data signal out port 108 to external medium 118.
As seen in FIGS. 1 and 2, within current Network Switches 10, the number of SerDes 124, the number of MACs 122, the size of Routing Tables 128, the capability of the Switch Fabric 124, the CPU 102 processing power, the packet processing power, and/or some other design constraint results in the Network Switch being able to support only a finite number of ports 108.
Some network switches have dedicated standby ports, also called redundant ports, which can be used in the event of a primary port failure. Standby or redundant ports are intended to be manually configured for active use in the event of a failure in a primary port. A primary port failure can occur due to a failure in the switching core, physical port transceivers, or a link connecting the primary port to the remote end. In any of these primary port failure cases, the network loses a connection path (i.e., a link) and therefore loses the ability to transmit all data between two end points in the network, unless an alternate or redundant path is established. However, a network architecture that relies on redundant and/or standby ports to be enabled in case of a failure of a primary port necessitates that such redundant or standby ports remain idle and do not carry data until needed. As a result, network data traffic throughput is still limited to the maximum number of active ports capable of being supported by the Network Switch.
Other network architectures refrain from utilizing all the available bandwidth of a Network Switch, so that in the event of a failure of a link, other ports in the Network Switch will have sufficient capacity available to handle the additional load from the failed link. However, this results in each Network Switch operating at less than maximum bandwidth and requires additional Network Switches to support a full bandwidth capability.
A data center network architecture is generally considered a static configuration, such that once a data center network is built out, the main architecture does not change and there are relatively few changes are made to the data center network. This is because each architectural modification or change requires sending personnel to the data center to manually move components (or equipment) and/or to change interconnections between the components (or equipment) within the data center, or to reprogram equipment in the data center. Each architectural modification or change to the data center network incurs cost, sometimes significant cost, and increases the risk of errors in the new data center network architecture, and the risk of failures resulting from the architectural modification or change.
Because of these risks, in most cases architectural modifications or changes to a completed data center network is restricted wherever possible to only replacing failed components, minor upgrades to components, adding minor new features or capabilities, or adding a few new connections. Generally, with such architectural modifications or changes, there is little change to the core data flow in the data center network.